More on that rescue on Mt. Hood caught on camera. A mountain climber saved after a terrifying fall. He plummeted hundreds of feet down the slope and ABC's John muller has the details. Reporter: This morning, 59-year-old Michael Adams is in serious condition after a dramatic black hawk helicopter rescue Saturday at Oregon's Mt. Hood. Our initial assessment was that it was quite grave. Reporter: Adams described by his son as an avid climber slipping while at an elevation of 10,000 feet and then plummeting 750 feet down a slope landing in what's called a fumerar. It looks like a sinkhole with a drain in it in the middle. I mean, you just -- if you fall on the mountain you're going to go down the drain. Reporter: It is essentially a crack in the mountain where steam and sulfur gases vent from a volcano. Portland mountain rescue says Adams is lucky to be alive. 15 members of their team were nearby in a training exercise when a 911 call came in. Scott Norton says it took the crew 30 minutes to reach him. This was definitely the most severe injuries that I've experienced on a mission. We were very concerned that he might not make it. Reporter: Rescuers say Adams was unable to move but could talk. He was pretty beat up, yeah. Expressing some pain. Some obvious trauma to his face. Reporter: Experts say it's very dangerous to hike the mountain in warmer weather. Since 2000, 40 have died climbing it. It's mother nature and she's in charge at the end of the day. Reporter: For "Good morning America," John muller, ABC news, New York.

This transcript has been automatically generated and may not be 100% accurate.